It has been conventionally known an electronic musical instrument which allows a user to edit a timbre used in a performance. For example, NPL1 discloses that the user can edit various parameters defining timbre in a voice mode of a synthesizer.
In such an electronic musical instrument, values of parameters edited by the user can be set in a tone generator unit, thereby generating an audio signal according to a performance operation by the user with timbre according to the values of parameters, and outputting sound according to the audio signal.
However, it is generally difficult to grasp relation between values of parameters and audibility of timbre, and the user adjusts values of various parameters while repeating listening again and again until a timbre with desired audibility is obtained.